help with sudden over boost!!

[chris999]

the other day i noticed that when i was in 5th and pushing the happy pedal down i was peaking at 24psi (which is not normal for my setup..ko3, revo), at the same time as that it ever so slightly splutter and slightly judder (not mis firing i don't think as i no wot that feels like). today i had my blueflame turbo exhaust fitted and sweet jesus it hit 25psi. now that would be good on something like a gt2rs but not on a baby ko3! any ideas..... as it boosts fine but hits that high and it doesn't like it (splutters slightly etc).
any diagnoses or advice would be really apreciated.
cheers.

 

[pdcupra]

dodgey N75, or your boost pipes arent man enough for the job and collapsing - i was going to tell you earlier but forgot, had this in my 306 hdi (boost pipes that is)

 

[beezaturbo]

n75 had the same on mine. 5th gear sat at 60 put my foot down saw 27psi then limp mode. swapped it all fine.
(ko3s by the way)

 

[chris999]

what is the n75? will it need replacing and how many shiny pennys will it cost?

 

[beezaturbo]

there about £25 loctaed slightly further forward then the dump vave on the turbo intake pipe leading to the airfilter.make sure when swapping it you plumbi tin the right way round

 

[nick s]

this happened to me shortly before my old K03s went bang and it's started again, also, occasionally the car will not boost over 4psi no matter what i do and i have to turn the car off and on again to correct it. any ideas chaps? getting annoying now! i will replace the n75 but will that sort the problem of losing boost randomly? i had VAg-com done the other day and it came up as multiple misfire on cylinder 4?

 

[acidstrato]

maybe a coilpack is on its way out., or you got a duff plug

you know the drill, clear it and see if it comes back

 

[beezaturbo]

have you cahnged the plugs since having it rempaped, or at all?
i replaced mine for the denso irridium ones and it sorted out a some crappy running i was having. dont think they'd been changed for ages.
a misfire wont be the n75 more then likely the coil pack

 

[nick s]

maybe a coilpack is on its way out., or you got a duff plug

you know the drill, clear it and see if it comes back

have reset it mate, will see if it comes back. when it came up, my mate popped my bonnet and my coil on cylinder 4 was alot higher than the others so he pushed it back down, suspecting this may be the cause of the problem. mine keep raising up every few days? do they all do this?

 

[beezaturbo]

no.

 

[acidstrato]

nope LOL maybe its just worn and isn't quite 'popped' in like it should or maybe something is obstructing it/pulling it out?

may be an idea to get a bolt down version in the future, no hassle then

 

[chris999]

i have recently changed all all spark plugs and coilpacks about 6-7000 miles ago, today i reset the battery, took all the spark plugs out and cleaned them up and checked the coilpacks for any obvious signs of wear etc. it isn't really a misfire and it boosts fine but just over boosts, and when it reaches 24psi-25psi it sort of holds back but it doesn't feel like your stereotypical misfire as i have had this whole coilpack problem before. i phoned up seat, audi, and volkswagon and they have priced it as £60. i gave them the part number that is in the sticky at the top of the mk3 ibiza section. i am slightly annoyed with it at the moment!

 

[creedy]

with the coil raising up couldn't that just be a loose spark plug

<this is for thinking


those bad boys are for dancing

 

[pdcupra]

try skoda too, someone got quoted much cheaper at skoda for a MAF than anywhere else......

 

[MIkey kc]

if its over boosting and slightly juddering you need to be careful that you dont melt a piston like me!!!! its not cheap! you should get it checke out quick!!

 

[chris999]

it is only over boosting by 2-3psi surely it would take more than that to blow a piston. i know it isn't coilpack/spark plug because it wouldn't over boost would? are the 'C' valves the same as the 'F' (N75).

 

[MIkey kc]

yeh they are different! they look the same and will still fit but some are stronger than others but cant tell you which one is better sory

 

[chris999]

can anyone help? i need to no what valve to go for whether it be C,F,J? i have revo etc.

 

[acidstrato]

nope the C and F valves are the same (ok not exactly otherwise they wouldnt be 2 different part numbers! but the are they same specification hence C and F valves were both used as standard)

melt a piston...WELL DONE that takes some doing! some people rag the tits off their cars and at worst they run out of fuel!

 

[chris999]

oh right because i have been told different, so what is the 'J' valve all about?